William De La Mare, (born , England—died c. 1290) English philosopher and theologian, advocate of the traditional Neoplatonic-Augustinian school of Christian philosophy, and leading critic of the Aristotelian thought introduced by Thomas Aquinas.

A member of the Franciscan order, William became a master of theology at the University of Parisc. 1275 and subscribed to the Augustinian school as expressed by the celebrated Italian Franciscan Bonaventure. While lecturing at Paris, William wrote his Commentarium super libros sententiarum (“Commentary on the Books of Sentences”—i.e.,annotations on Peter Lombard’s 12th-century collection of patristic and early medieval theology). Reflecting his Augustinian intellectual development, William considered the knowing process to be the operation of an inherent power in the human spirit given by God at creation. According to William, man’s intrinsic desire to reunite with God, and an inner enlightenment of the soul (illuminationism) by which eternal ideas are recognized, constituted the essence of human psychology.

On returning to England William wrote his chief work, Correctorium fratris Thomae (1278; “Corrective of Brother Thomas”), a critique of the writings of Thomas Aquinas. The introduction of Aristotelian thought into theology drew a volatile reaction from the traditional Neoplatonic thinkers, who had dominated Western thought since Augustine. Desirous of providing students with a guide to control these new thoughts, William chose 118 articles from Aquinas’ writings, mostly from his celebrated Summa theologiae (“Sum of Theology”), and noted points at which Aristotelian influence produced concepts or interpretations contrary to orthodox formulas. Historians of philosophy, however, observe that William failed to analyze the basic questions causing conflict between Thomistic Aristotelians and Neoplatonists—i.e., the distinction between essence and existence, time and eternity, matter and spirit.

William’s Correctorium was approved for the entire Franciscan order in 1282, when the Franciscan minister general Bonagratia forbade the study of Aquinas’ Summa theologiae except by scholars using the critical standard of William’s Correctorium. After publication, the Correctorium, in a publicized polemic, was in turn corrected by Thomists, notably the English Dominicans Richard Clapwell and Thomas Sutton and the French Dominican John of Paris. Entitling their response Correctorium corruptorii fratris Thomae (“Corrective of the Corruptor of Brother Thomas”), the Thomists emphasized William’s failure to comprehend both Aquinas and Aristotle. The surviving texts of the Correctoria, edited by P. Glorieux (1927), with comments by F. Pelster (1956), probably do not give William’s original version but only preserve a revision that he completed c. 1284.

Of parallel importance were William’s contributions to biblical studies. His Correctio textus bibliae (“Corrective of the Text of the Bible”) and the De Hebraeis et Graecis vocabulis glossarum bibliae (“On the Hebrew and Greek Terms of Biblical Annotations”) are considered among the most learned from the medieval period.